论文标题
矢量电流的病房身份和$η_c\rightArrowγ$ rattice qcd中的衰减率
Ward Identity of the Vector Current and the Decay Rate of $η_c\rightarrowγγ$ in Lattice QCD
论文作者
论文摘要
使用最近提出的方法ARXIV：1910.11597（Yu Meng等），我们使用两个$ n_f = 2 $ twisted Masseguge semembles的$η_c$ $η_c$的两光子衰减率具有晶格间距$ 0.067 $ 0.067 $ FM和$ 0.085 $ 0.085美元。从这两个集合中获得的结果可以以幼稚的方式推断到连续限制，从而产生与两个标准偏差内实验性的结果一致的结果。具体而言，我们获得了$η_c$的两光衰变的结果，为$ \ Mathcal {b}（η_c\ rightArow2γ）= 1.29（3）（3）（3）（18）\ times 10^{ - 4} $，其中第一个错误是统计的，第二个错误是由有限的lattice lattice spacics spacics spacicsing造成的，这是我们的第二个错误。事实证明，在这种新方法中，矢量电流的病房身份至关重要。我们发现，在有限的晶格间距的情况下，对当地电流违反了病房的身份，但是在采取连续性限制后将进行恢复。
Using a recently proposed method arXiv:1910.11597 (Yu Meng et al.), we study the two-photon decay rate of $η_c$ using two $N_f=2$ twisted mass gauge ensembles with lattice spacings $0.067$fm and $0.085$fm. The results obtained from these two ensembles can be extrapolated in a naive fashion to the continuum limit, yielding a result that is consistent with the experimental one within two standard deviations. To be specific, we obtain the results for two-photon decay of $η_c$ as $\mathcal{B}(η_c\rightarrow 2γ)= 1.29(3)(18)\times 10^{-4}$ where the first error is statistical and the second is our estimate for the systematic error caused by the finite lattice spacing. It turns out that Ward identity for the vector current is of vital importance within this new method. We find that the Ward identity is violated for local current with a finite lattice spacing, however it will be restored after the continuum limit is taken.
